Magnetic alignment of mesophase pitch-based carbon fibers

Mesophase pitch-based carbon fibers (MPCFs) have recently been developed for use as high performance anode materials in Li ion secondary batteries, having a microscopic as well as macroscopic structure especially suitable for Li storage, Because of the highly anisotropic diamagnetic moment observed between 50 and 310 K in pristine milled MPCF segments, they can easily be oriented parallel to an applied magnetic field, as observed by scanning electron microscopy. A simple model is proposed to explain both the observed alignment of undoped fibers and the suppression of alignment in B-doped MPCFs for relatively small applied magnetic fields, because of their smaller diamagnetic moment. (C) 1996 American Institute of Physics.